The present invention relates to vehicle bumper systems, and in particular relates to a hybrid bumper system adapted to provide styling flexibility, cost effectiveness/competitiveness of and manufacture assembly, and high strength in combination with reduced weight, and high efficiency and predictability of energy management on impact in terms of amount of energy absorbed and amount of energy transmitted to the vehicle frame along each portion of a bumper crush sequence.
Bumper systems for modern passenger vehicles continue to evolve, both in terms of functional aspects and also aesthetics. These requirements are often conflicting, and hence there is a need for a hybrid bumper system adapted to take advantage of different materials while still maintaining optimal control of things such as assembly time, cost, and energy management. For example, recently, government and insurance standards are beginning to focus on optimizing bumper systems to provide reduced injury to pedestrians during impact while continuing to provide optimized energy management during high speed and low speed impacts. This requires that energy absorption and impact characteristics be designed with particular energy absorption profiles during different portions of the bumper stroke. However, the bumper system must accomplish the impact energy management while maintaining styling flexibility, low weight, low cost, high strength-to-weight ratio, and short lead times for tooling. Styling flexibility is required to permit product differentiation, including the ability to provide a chrome look. Preferably, the bumper system should use reusable and/or recyclable materials that are environmentally friendly. Also, it is desirable to minimize the number of components used in the bumper system, including such things as accessory mounting structure (e.g., an integrated fog lamp support structure, an integrated grill support structure), integrated air flow management, other integrated bumper functions (e.g. steps, license plate mounting, and/or towing capability), and the like.
In addition to functional requirements, it is desirable to provide a bumper system that is distinctive and that also offers the ability and flexibility to provide different aesthetics. However, customers typically want an integrated solution that looks well designed. It is typically not an acceptable solution to merely mount additional components onto the exterior of existing systems, since the result may have the appearance of an un-integrated component placed on the assembly as an afterthought. Also, “add on” components add weight and cost to the assembly without substantial benefit.
Hybrid bumper systems using components made of different materials provide an opportunity to optimize particular components for particular design requirements. However, this can also lead to an increase in the number of components and/or to an increase in assembly costs. Also, it can lead to a variety of quality problems related to mismatch of materials and their different properties at various temperatures. For example, dissimilar materials can result in dimensional control problems and tolerance/stack-up problems, thermal expansion problems and attachment difficulties causing inconsistencies and reduced durability, and the like.
Thus, a bumper system having the aforementioned advantages and solving the aforementioned problems is desired.